The present invention relates to a shaft and rotatable machine element assembly and more particularly to a unique structural arrangement for a shaft and gear assembly wherein the hub of a gear is slidably mountable upon a rotatable shaft having a radially extending projection member, the hub being restrained from rotational movement on the shaft through a fastening arrangement cooperable between the hub and projection member.
It has been long known in the machine design art to fasten a gear (or other rotatable machine element such as a disk or sheave); slidably mountable on a rotatable shaft by either passing a pin member through aligned apertures or lateral recesses in the hub of a gear and in the shaft on which the gear has been mounted or by threading a pin in the form of a set screw through an aperture in the shaft hub with the end of the pin or set screw engaging tightly against the peripheral wall of the shaft when the threaded set screw is rotated in a preselected direction. Both of these well known aforedescribed arrangements often require stress-inducing drilling in the gear hub or other complex steps to provide the aperture in the hub with load accommodating characteristics being limited by the relative geometry, location and manner of engagement between pin and hub. Further, the frictional engagement arrangement of the threaded pin or set screw end against the shaft surface has resulted in problems of rotational slippage. Moreover, in the arrangement where a pin extends through aligned apertures in the hub and shaft, accurate drilling and aligning steps have been required in manufacture and assembly, these steps being comparatively time-consuming and expensive.
Recognizing these problems of past arrangements, the unique structural arrangement of the present invention provides a shaft and gear assembly which is straightforward and economical in both manufacture and assembly, requiring a comparative minimum of steps in both operations. Further, the novel structural arrangement of the present invention minimizes past problems of aperture alignment between hub and shaft without sacrificing the ability of the assembly to accommodate both bi-directional axial and torsional loads and, in fact, serve to optimize the distribution and accommodating capacity for axial and torsional loads. In addition, the structural assembly arrangement of the present invention integrates a novel spacer structure into the assembly, allowing for compact axial adjustment of a preselected number of interlocking spacers in accordance with usage demands. Further, the structural features of the present invention can be effectively and efficiently employed with various configurations and sizes of gear and shaft arrangements, allowing for quick and efficient interchange of the several parts of the structural assembly.
Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein.